This invention relates to an apparatus for returning a movable member from a remote position to a reference position. More particularly, this invention relates to an occluder which controls the direction of travel of a moveable member and determines the location of a reference position of the moveable member.
In various types of instrumentation, particularly ophthalmic instruments, such as an optometer it is frequently desirable to be able to automatically return a moveable member, such as a carriage, to a known reference position.
It is an object of the present invention to provide an apparatus for automatically returning a carriage to a reference position.
It is a further object of the present invention to provide an occluder for determining the direction required to move the carriage to a reference position.
It is still another object of the present invention to use an occluder in combination with an energy beam for determining the location of the reference position of the carriage.